Engineers examining concrete from Davis-Besse

TNS Regional News
•
Mar 26, 2014 at 10:46 AM

With less than a month to go for area residents to weigh in on FirstEnergy Corp.’s application to extend Davis-Besse’s operating license by 20 years, nuclear engineers are scrutinizing concrete samples from the plant’s shield building to see if the structure is still strong enough to protect the reactor from exterior threats.

Some tiny, previously unseen cracks in the shield building have been found since the original laminar ones were discovered in fall 2011.

Engineers for the utility and the Nuclear Regulatory Commission are trying to get to the cracks’ root cause to determine if they might be symptoms of additional cracking or simply were missed during fall 2011. The original cracks were blamed on harsh conditions from the Blizzard of 1978. Davis-Besse was built during the 1970s, but its shield building was not weatherproofed until 2012.

David Hills, engineering branch chief for the NRC’s Midwest regional office in Lisle, Ill., told The Blade after the afternoon part of a two-part meeting in the Camp Perry clubhouse Tuesday the added cracks have been found over the last two years since the plant was allowed back into operation. As a condition for restart, FirstEnergy agreed to drill out tiny core bore samples so that the shield building’s concrete could be examined closely inside a lab.

Those newly found cracks are tiny imperfections. But Mr. Hills said they could provide big clues about how the shield building is aging.

The NRC needs to know whether the shield building can protect the reactor from what Mr. Hills described as “tornado-generated missiles,” such as utility poles lofted by twisters.

“There’s some thought the cracking that’s in there now is slowly growing,” Mr. Hills said. “If there is growth there, it’s important to know the root cause.”

FirstEnergy is on schedule to give its findings to the NRC in late spring or early summer, said Ray Lieb, Davis-Besse site vice president.

Federal engineers will review the report and give them to the agency’s Advisory Committee for Reactor Safeguards, a panel of engineers that works independently of the NRC staff. The advisory committee is expected to have a meeting on the issue in Washington this fall, said Jennifer Young, a FirstEnergy spokesman.

The cracks in question are separate from an extensive void found near the top of a hole FirstEnergy cut recently through the shield building to install Davis-Besse’s two new steam generators, a $600 million investment.

That void has been attributed to problems with sealing a hole in the same spot two years ago after an exchange of reactor heads.

FirstEnergy has said the shield building has stayed strong enough to repel objects during the last two years, despite the gap. Mr. Hills said the NRC is still assessing that claim.

No mention of the lab work was made during the NRC’s afternoon session. The evening session would have been the last chance for residents to deliver verbal statements about the plant’s continued operation. The agency will take written comments through April 21.

The NRC held Tuesday’s pair of meetings to discuss potential environmental impacts from an extra 20 years of plant operation, but almost every speaker during the afternoon session was a public official, labor union representative, or industry supporter who cited Davis-Besse’s contribution to the local economy.

Brian Dicken, vice president of public affairs for the Toledo Regional Chamber of Commerce, cited a report that put Davis-Besse’s annual economic impact at $440 million. The plant’s 700 regular, full-time employees have a combined $61 million annual payroll, and the plant supports 668 other jobs that add millions of dollars more to the economy, the report said.

Guy Parmigian, superintendent of the Benton-Carroll-Salem Schools, said 20 percent of his district’s annual revenues comes from Davis-Besse’s $5.8 million in annual property taxes.

Jo Ellen Regal, Ottawa County Commission president, said Davis-Besse’s $13 million in state and local taxes generate jobs and keep property taxes down for Ottawa County residents in general.

Mr. Hills said it’s possible to reopen the plant’s safety assessment, depending what FirstEnergy and NRC engineers find in the most recent concrete samples and from NRC’s asessment of the shield building’s void. The agency signed off on a safety analysis, the other major requirement for extension last fall.

The NRC granted extensions to two-thirds of the nation’s operating reactors — rejecting none — before freezing the process in 2012. Davis-Besse’s license is set to expire April 22, 2017.

Most opponents of the license extension said they would be at the evening session. Terry Lodge, a Toledo attorney and anti-nuclear activist, urged the NRC to seek “renewable alternatives to a risky, dubious Davis-Besse license extension.”